This invention has to do with dispensers for fluid products. Certain aspects of our proposals are particularly useful in relation to the dosing of medicines, but the proposals have wide application.
We are concerned with pump dispensers, having a pump chamber with a valved inlet communicating with a supply container for fluid product. An outlet from the pump chamber is preferably also valved. The pump chamber volume is changed from maximum to minimum in a pumping stroke of a pump plunger moving relative to a pump body. The pump chamber may be defined by a deformable container or, more usually, between piston and cylinder components comprised in or carried by one or other of the body and plunger. In moveable-nozzle dispensers the outlet is in the plunger. In fixed-nozzle dispensers the outlet is in the body. Most of these dispensers have a generally vertically-operating plunger and the pump is mounted at the top of a container for the product, but variants are known.
Any volume can be dispensed, including only a part of the pump chamber volume, but the availability of a fixed-volume dose corresponding to the pump chamber volume is significant. One possible dosing application is in the administration of liquid medicines to humans or animals.